The telephone industry uses thousands of miles of buried or underground air core cable to transmit telephone signals. These air core cables commonly comprise 100 or more tansmission wire pairs encased in a plastic sheath. In some applications the cables may be much larger and carry far larger numbers of wire pairs. These buried cables can collect internal moisture which results in undesirable changes in the capacitance between the wires of the wire pairs as well as corrosion and shorting of the wire pairs. Conventionally, when these moisture problems occur, the telephone companies are requred to dig up and replace the telephone cable. The cable is expensive, and the labor involved in digging up and replacing long sections of cable is costly.
In an effect to avoid these high maintenance costs, some telephone companies have sought to cure the effects of moisture in a cable by blowing dry air through the cable to remove moisture. These maintenance efforts require discharge of air through the cables for extended periods of time, and once completed, may be only temporary because moisture may reenter the cable. Additionally, the discharge of air through the cable does not cure problems caused by the formtion of corrosion or shorting of the wire pairs. That corrosion will continue to cause detrioration of the electrical transmission capability of the wire pairs in the cable.
In other prior art efforts to cure these problems in telephone transmission, various liquids have been injected into the cable in an effort to remove the moisture from the cable and dissolve corrosion, but such efforts have been unsuccessful.